struts标签

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 <1>struts标签:logic标签

1.<logic:equal> and so on比较标签
 以下eg都是由一个servlet转发过来的
  MyBean mb = new MyBean();
  mb.setName("yc");
  mb.setCount(200);
  request.setAttribute("mybean",mb);
  request.getRequestDispatcher("jsp1.jsp").forward(request,response);

 eg1:<bean:define id="myint" value="100"/> //当前页面定义一个字符串
            <logic:equal name="myint" value="100">
            myint=100
           </logic:equal>

 eg2:<bean:define id="bean3" name="mybean" scope="request"/> //从request上获取bean
           <logic:lessThan  name="bean3" property="count" value="200.a"> //比较bean的count属性和200.a
           bean3 LessThan 200.a
          </logic:lessThan>

 注意:如果两个字符串都能够成功转为数字,则是比较数字的大小,否则像eg2就是比较字符串的大小

 eg3:<bean:define id="bean1" name="mybean" property="name" scope="request"/>
            <logic:equal name="bean1" value="yc">
            name1=yc
           </logic:equal>

 eg4:<bean:define id="bean2" name="mybean" scope="request"/>
           <logic:equal name="bean2" property="name" value="yc">
           name2=yc
          </logic:equal>
 
 注意:eg3和eg4都是比较bean属性,只是写法不同

 eg5:比较请求参数

      <logic:equal parameter="id" value="150">
      <bean:parameter id="myid" name="id"/>
       parameter:<bean:write name="myid"/>=150
      </logic:equal>

2.<logic:match>
 查看指定字符串是否被包含
 <logic:match name=""    value="被包含字符串"    location="start/end也可以不写,就是任意位置"/>

 eg:<bean:define id="bean4" name="mybean" property="name" scope="request"/>
         <logic:match  name="bean4" value="y" location="start">
          yc is start with bean4
         </logic:match>

3.< logic:iterator>
 a.遍历Vector等集合,value形式的
 <logic:iterator    id="每个集合的元素"    name="集合在当前页面的绑定名"    indexId="序号"   
             offset="起始位置,0开始"    length="遍历长度"/>
 
      前提:  Vector v = new Vector();
                    v.add("dog");
                    v.add("girl");
                    v.add("bird");
                    v.add("cat");
                    request.setAttribute("myvector",v);
                    request.getRequestDispatcher("jsp1.jsp").forward(request,response); 


 eg1:<bean:define id="vector1" name="myvector" scope="request"/>
            <logic:iterate id="element" name="vector1">
            <bean:write name="element"/>
            <br />
            </logic:iterate>

 eg2:<bean:define id="vector2" name="myvector" scope="request"/>
            <logic:iterate id="element" name="vector2" indexId="index" offset="1" length="3">
            <bean:write name="index"/>.<bean:write name="element"/><br />
            </logic:iterate>

 b.遍历Map等,key/value形式
    只是输出的时候有所不同
   <bean:write   name=""    property="key"/>输出元素的key部分
   <bean:write   name=""    property="value"/>输出元素的value部分

 前提:  HashMap hm = new HashMap();
  hm.put("yc","yuechen");
  hm.put("tjs","tianjinsong");
  hm.put("xc","xiaocen");
  hm.put("xk","xukai");
  request.setAttribute("mymap",hm);

 eg:<bean:define id="map1" name="mymap" scope="request"/>
         <logic:iterate id="element" name="map1" indexId="index">
         <bean:write name="index"/>.<bean:write name="element" property="key"/>:<bean:write name="element"   property="value"/><br />
        </logic:iterate>
 
  c.遍历map中的集合
  双层iterator,内层iterator需要加入property="value"


  前提:  HashMap hm2 = new HashMap();
               String[]asia = {"china","japan","korea"};
               hm2.put("asia",asia);
               String[]erop = {"greman","rasa","england"};
               hm2.put("erop",erop);
               String[]us = {"usa","canada"};
               hm2.put("us",us);
               request.setAttribute("country",hm2);

  eg:<bean:define id="myc" name="country" scope="request"/>
          <logic:iterate id="element" name="country" indexId="index">
          <bean:write name="index"/>.<bean:write name="element" property="key"/><br />
          <logic:iterate id="inelement" name="element" indexId="inindex" property="value">
          -----<bean:write name="inindex"/>.<bean:write name="inelement"/><br />
          </logic:iterate>
         </logic:iterate> 

<2>struts标签:bean标签

1.<bean:page>
 当前页面获取jsp页面内置对象
 <bean:page   id="当前页该内置对象的绑定名"   property="jsp内置对象名"/>
 jsp内置对象:application
                          session
                          request
                          response
                          config

eg1:<bean:page id="mySession" property="session"/>
    输出session创建时间:<bean:write name="mySession" property="creatTime"/>
    输出sessionID:<bean:write name="mySession" property="id"/>

eg2: <bean:page id="myApplication" property="application"/>
    服务器信息:<bean:write name="myApplication" property="serverInfo"/>

注意:严格区分内置对象属性的大小写,可以用 <% session.XXX %> 看看session都有什么方法


2.<bean:include>
 包含资源,将资源用一个变量代替
 <bean:include   id="当前页面的绑定名"   forward="Global-Forward名" />
 <bean:include   id="当前页面的绑定名"   page="jsp页面相对路径,用/开头" />
 <bean:include   id="当前页面的绑定名"   href="完整url" />

 显示资源
 <bean:write name="绑定名" filter="是否显示原样html标记,默认true,显示,应该设置为false" />

eg1:<bean:include id="jsp2" page="/jsp2.jsp"/>
     <bean:write name="jsp2" filter="true"/>

eg2:<bean:include id="jsp3" forward="myForward"/>
     <bean:write name="jsp3" filter="false"/>


3.<bean:define>
 在toScope作用域(可以不写,默认page)上定义(绑定)一个变量,代表scope作用域(可以不写,默认从page找到application)上的
 字符串,或者javabean,或者javabean的属性
输出字符串:value是字符串的值,只有在此时才能用value属性
 eg1:<bean:define id="myString" value="yc"/>
            <bean:write name="myString"/>
输出bean属性值:
 已知当前jsp页面接受控制器发来的如下:
  MyBean mb = new MyBean();
  mb.setName("jrunner");
  request.setAttribute("mybean",mb);
  request.getRequestDispatcher("jsp1.jsp").forward(request,response);
 
 eg1:<bean:define id="beanname1" name="mybean" property="name" scope="request"/>
      <bean:write name="beanname1"/>

 eg2:<bean:define id="beanname2" name="mybean" scope="request"/>
      <bean:write name="beanname2" property="name" />
 注意:eg1,eg2相当于:<%=((MyBean)(request.getAttribute("mybean"))).getName() %>
           注意scope可以不写,但是建议写,严格和request.getAttribute比较

 eg3:<bean:define id="beanname3" name="mybean" type="demo.MyBean" scope="request"/>
      <bean:write name="beanname3" property="name" />

 eg4:<bean:define id="beanname4" name="beanname3" type="demo.MyBean" scope="page"/>
      <bean:write name="beanname4" property="name"/>
 注意:eg4 的beanname4是从page上面获得的beanname3,type属性可以不写
       name:只能是绑定名
      

4.<bean:size>
 输出集合长度

eg:在request上面绑定了HashMap类型的集合,绑定名是mymap,然后转发jsp页面

 <bean:size id="length" name="mymap" scope="request"/>
        <bean:write name="length"/>
    

5.<bean:write>
 可以按照指定的格式输出,加format属性

eg1:request.setAttribute("myfloat",Float.valueOf("3.1"));

     <bean:define id="myf" name="myfloat" scope="request"/>
     <bean:write name="myf" format="#.###########"/>
     这个时候会得出3.09999990463
 

  
6.<bean:parameter>
 获得请求参数
    一个参数的情况:
 <bean:paramter   id="当前页面请求参数的绑定名"    name="请求参数名"    value="请求参数默认值(可以不写)" />
 <bean:write    name="当前页面请求参数的绑定名" />
    n个参数的情况: